STIEBEL ELTRON WWK 300 A - On the System; Safety Valve (on-site); Pressure Reducing Valve (on-site); Regular Valve Maintenance

9
Protective anode
!
PLEASE NOTE: The sacrificial
anode must be checked by a
qualified contractor 12months after
the unit has been installed and checked
periodically thereafter as advised by
the qualified contractor. Failure to do so
may void your warranty.
An anode for the protection of the
DHWcylinder is inserted centrally from
the top into the DHW ccylinder of the
appliance (Fig.3, pos. 12). The anode
fitted at the factory (anode rod) is
approximately 1.26 m long.
Replace the anode with a new one if the
installed one has been consumed.
A cap over the anode terminal prevent the
ingress of water between the anode ter-
minal and the condensate pan. Remove
the cap if you need to remove the anode.
When installing the anode, ensure that
the metallic conductor connection is
correctly made. It’s recommended for
first anode inspection to happen one year
after installation.
Consult with your water specialist, or
contractor, for the optimum timing for
inspections thereafter. Should it be
impossible to insert a rod anode, you may
have a sectional anode installed instead.
In areas where total dissolved solids
(TDS) in the water is outside the range
40-400 mg/l, the magnesium alloy anode
supplied, M2, must be replaced. Use a
high potential, M1, anode if TDS<40
or an aluminium A5 alloy anode if
TDS>400, before installing the unit.
Push the cap back over the anode termi-
nal.
Cleaning the evaporator
Maintaining the full output of the
WWK300 requires an occasional
professional cleaning of the evaporator.
Clean the evaporator only with water
and a brush. Never use acidic or alkaline
cleaning solutions.
WARNING Injury risk
The evaporator has many
sharp-edged fins. When clean-
ing the evaporator, proceed
with caution and wear pro-
tective clothing, in particular
safety gloves.
Further information regarding the
equipment:
z Descaling (only if a booster heater is
installed)
— Close the shut-off valve in the cold
water supply to the tank.
— Draw water from the tank to
relieve the pressure inside the
appliance.
— Unscrew the booster heater flange.
To undo the flanged immersion
heater, you require a 1½“ pipe
wrench. The pipe wrench must be
hollow so it can be guided over the
connecting cables.
— Immerse scaled sections of the
heater rod into a descaling liquid
(for example citric acid), until the
limescale has dissolved from the
heater rod.
— Flush the descaling liquid off and
allow the immersion heater to dry.
z Draining the cylinder:
— Close the shut-off valve in the cold
water supply.
— Fully open the hot taps at all draw-
off points.
— The cylinder is drained via the
cold water inlet line. Open the
drain valve (fig. 1, pos. 6). If no
drain valve was installed, undo the
fitting on the cold water supply
of the appliance. Residual water
remains in the lower part of the
cylinder.
Note: Hot water can be expelled
during draining.
On the system
Safety valve (on-site)
This valve opens when the water pressure
exceeds the preset value of 0.7MPa
(7 bar) thereby relieving the pressure. It is
adjusted so that no water will be expelled
when heating is switched OFF. Should it
continue to drip excessively, either the
valve seat has become contaminated, the
water pressure is too high or the pressure
reducing valve has become faulty.
Pressure reducing valve (on-site provi-
sion)
Check the valve for perfect function.
Replace it, if required.
Regular valve maintenance
Safety requires that valves are regularly
checked for perfect function. For this,
regularly vent the safety valve until a full
stream of water flows from it. Close the
safety valve after checking.
How quickly limescale builds up depends
on the local water quality.
As your local contractor is familiar
with your local water quality, let him
determine the timing of this check.
!

WARNING
If the hot water unit is not used
for two or more weeks, an amount of
highly flammable hydrogen gas may
accumulate in the water tank. To dissi-
pate this gas safely, it is recommended
that a hot tap be turned on for several
minutes or until discharge of gas ceas-
es. Use a sink, basin or bath outlet, but
not a dishwasher, clothes washer or
other appliance. During this procedure,
there must be no smoking, open flame
or any electrical appliance operat-
ing nearby. If hydrogen is discharged
through the tap, it will probably make
an unusual sound as with air escaping.